Postgres SQL query slow with large table (AWS RDS)-CodePudding

Currently the table have minimum row of 30million, and it is growing, whenever try to do SELECT query, it take extremely long time. What need to optimize the query before I increase the performance of the database?

POSTGRES 12 on AWS RDS db.t3.small, with 20GB storage

**Message Table**

id (bigint) -> pk
meta (jsonb)
snapshot_ts (integer) -> epoch timestamp
value (character varying 100)
type (character varying 50)
created (timestamp with timezone)
last_modified (timestamp with timezone)
attribute_id (bigint) -> Foreign Key
company_id (bigint) -> Foreign Key
project_id (bigint) -> Foreign Key
device_id (bigint) -> Foreign Key


EXPLAIN (analyze,buffers) SELECT COUNT(*) FROM public.message
WHERE company_id=446 AND project_id=52 AND snapshot_ts>=1637568000.0 AND snapshot_ts<=1637654399.0 AND attribute_id=458

->Aggregate  (cost=399804.26..399804.27 rows=1 width=8) (actual time=65150.696..65150.697 rows=1 loops=1)
  Buffers: shared hit=170 read=115437 dirtied=167
  I/O Timings: read=64396.424
  ->  Index Scan using message_attribute_id_6578b282 on message  (cost=0.56..399803.23 rows=411 width=0) (actual time=57752.297..65147.391 rows=8656 loops=1)
        Index Cond: (attribute_id = 458)
        Filter: ((company_id = 446) AND (project_id = 52) AND ((snapshot_ts)::numeric >= 1637568000.0) AND ((snapshot_ts)::numeric <= 1637654399.0))
        Rows Removed by Filter: 106703
        Buffers: shared hit=170 read=115437 dirtied=167
        I/O Timings: read=64396.424
Planning Time: 0.779 ms
Execution Time: 65150.730 ms

**Indexes**
indexname                       | indexdef
message_attribute_id_6578b282   | CREATE INDEX message_attribute_id_6578b282 ON public.message USING btree (attribute_id)
message_company_id_cef5ed5f     | CREATE INDEX message_company_id_cef5ed5f ON public.message USING btree (company_id)
message_device_id_b4da2571      | CREATE INDEX message_device_id_b4da2571 ON public.message USING btree (device_id)
message_pkey                    | CREATE UNIQUE INDEX message_pkey ON public.message USING btree (id)
message_project_id_7ba6787d     | CREATE INDEX message_project_id_7ba6787d ON public.message USING btree (project_id)

CodePudding user response：

Considering the specific query:

SELECT COUNT(*)
FROM public.message
WHERE company_id=446 
  AND project_id=52 
  AND snapshot_ts>=1637568000.0 AND snapshot_ts<=1637654399.0 
  AND attribute_id=458

the following index has the potential of greatly increasing the performance:

create index ix1 on public.message (
  company_id, project_id, attribute_id, snapshot_ts
);

However, keep in mind that creating an index on a 30-million row table can take some time.